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000
FXUS64 KFWD 101113
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
613 AM CDT MON MAR 10 2014

.AVIATION...
SHALLOW FOG FORMING AS I WRITE THIS...BUT IT WILL DISSIPATE
QUICKLY AS WINDS START MIXING DOWN AFTER SUNRISE. ONCE IT IS
GONE...VFR SHOULD CONTINUE THROUGH REST OF TAF PERIOD. 84

&&


.PREV DISCUSSION... /ISSUED 351 AM CDT MON MAR 10 2014/

EARLY MORNING WATER VAPOR SATELLITE IMAGERY SHOWED A SHORTWAVE
TROUGH OVER NORTHWESTERN MEXICO AND ANOTHER...BUT MUCH MORE
COMPACT...SHORTWAVE TROUGH OVER SOUTHWEST OK AND THE TX PANHANDLE.
07Z SURFACE OBSERVATIONS SHOWED SOME PATCHY FOG DEVELOPING IN AREAS
GENERALLY ALONG AND EAST OF A LINE FROM BONHAM TO TERRELL TO
CAMERON. LIGHT WINDS AND CLEAR SKIES WERE OBSERVED OVER THESE
AREAS WITH SOUTH WINDS HOLDING UP AT 5 MPH OR STRONGER TO THE
WEST. DO NOT THINK FOG WILL DEVELOP MUCH FARTHER WEST THAN ITS
CURRENT POSITION AS A RESULT. A REGIONAL LOOK AT 07Z SURFACE
OBSERVATIONS INDICATED WEAK LEE SIDE CYCLOGENESIS OVER THE CENTRAL
HIGH PLAINS WITH 12 HOUR PRESSURE FALLS OF AROUND 3 MB OBSERVED
OVER EASTERN COLORADO.

TODAY AND TONIGHT...IN THE SHORT TERM...WILL CONTINUE TO MONITOR
THE DEVELOPING FOG OVER THE EASTERN CWA EARLY THIS MORNING. THE
PARIS AWOS WAS THE ONLY OBSERVATION INDICATING DENSE FOG ACROSS
THE CWA EARLY THIS MORNING...BUT IF DENSE FOG BECOMES MORE COMMON
MAY HAVE TO ISSUE A DENSE FOG ADVISORY FOR SOME OF THE EASTERN
COUNTIES BEFORE SUNRISE. ANY FOG THIS MORNING IS EXPECTED TO BE
FAIRLY SHALLOW IN NATURE AS THE 00Z FWD SOUNDING INDICATED A
FAIRLY DRY LOWER TROPOSPHERE YESTERDAY EVENING. WITH NO
SIGNIFICANT ADVECTION OF MOISTURE OVERNIGHT...THE FOG CAN BE
EXPECTED TO BURN OFF QUICKLY AFTER SUNRISE.

OTHERWISE...THE NORTHWEST MEXICO SHORTWAVE TROUGH/UPPER LOW IS
EXPECTED TO MOVE EAST THROUGH THE DAY TODAY...PASSING BACK OVER
TEXAS THIS EVENING. ALL MODEL GUIDANCE INDICATES THIS
SCENARIO...HOWEVER THIS TROUGH WAS NOT MOVING EAST AT THE TIME OF
THIS DISCUSSION ACCORDING TO SATELLITE IMAGERY. EVEN IF THE
EASTWARD MOVEMENT OF THE TROUGH IS SLOWER THAN EXPECTED...IT IS
EXPECTED TO REMAIN TOO FAR SOUTH TO BRING ANY SIGNIFICANT
PRECIPITATION CHANCES TO NORTH TEXAS TODAY OR TONIGHT.

MAINTAINED 20 POPS FOR LOCATIONS ALONG AND SOUTH OF A LINE FROM
GOLDTHWAITE TO PALESTINE FOR THIS AFTERNOON THROUGH THE OVERNIGHT
HOURS AT THIS TIME BECAUSE HIGH RESOLUTION MODEL GUIDANCE DOES
BRING PRECIPITATION UP VERY CLOSE TO THE CENTRAL TEXAS PORTION OF
THE CWA DURING THIS TIME PERIOD. SMALL PRECIPITATION CHANCES ARE
WARRANTED IN THE OPERATIONAL MODEL MASS FIELDS AS WELL...ALTHOUGH
NO QPF IS GENERATED OVER THE CWA. ISENTROPIC LIFT IN THE H850 TO
H700 LAYER IS OBSERVED IN MOST GUIDANCE...SO WOULD NOT BE
SURPRISED IF A FEW SHOWERS DEVELOPED OVER CENTRAL TEXAS THIS
AFTERNOON. ANY RAINFALL THAT DEVELOPS IS EXPECTED TO REMAIN VERY
LIGHT WITH MOST LARGE SCALE LIFT/SUPPORT REMAINING SOUTH OF THE
CWA...CLOSER TO THE UPPER LOW. A HUNDREDTH OF AN INCH OR TWO OF
RAINFALL IS ABOUT ALL THAT IS EXPECTED...IF ANYTHING DEVELOPS AT
ALL.

TUESDAY...A STRONG SHORTWAVE TROUGH...CURRENTLY SITTING OFF SHORE
THE NORTHERN CALIFORNIA COAST...COINCIDENTALLY NEAR THE EPICENTER
OF THE OVERNIGHT EARTHQUAKE...IS EXPECTED TO MOVE EAST OVER THE
WESTERN CONUS. THIS WILL SPREAD A STRONG BAND OF WESTERLIES ALOFT
OVER THE CENTRAL CONUS ROCKIES RESULTING IN STRONG LEE SIDE
CYCLOGENESIS FROM MONDAY AFTERNOON THROUGH TUESDAY MORNING. ON
TUESDAY...THE LEE SIDE CYCLONE IS EXPECTED TO PULL OFF THE HIGH
PLAINS AND MOVE SOUTHEAST OVER NORTH TX BY LATE TUESDAY AFTERNOON.
BASED ON THE EXACT TRACK AND STRENGTH OF THIS LOW PRESSURE
SYSTEM...WE MAY SEE SOME CRITICAL FIRE WEATHER DANGER ACROSS PARTS
OF THE WESTERN CWA. AT THIS TIME...MOST GUIDANCE KEEPS THE CENTER
OF THE SURFACE LOW JUST SOUTHEAST OF CHILDRESS LATE TUESDAY
AFTERNOON.

IF THIS VERIFIES...A DRYLINE PUNCH INTO THE WESTERN CWA IS
UNLIKELY AS THE POSITION OF THE SURFACE LOW WITH RESPECT TO THE
CWA IS UNFAVORABLE FOR STRONG WESTERLY WINDS. AN EXPLANATION AS TO
WHY THE DRYLINE PUNCH IS UNLIKELY FOLLOWS...SKIP THE NEXT
PARAGRAPH TO GET BACK TO THE FORECAST DISCUSSION...

THE PRESSURE GRADIENT FORCE WILL FAVOR A SOUTHEASTERLY WIND IF
THE SURFACE LOW IS OFF TO OUR NORTHWEST TUESDAY AFTERNOON. SURFACE
WINDS WILL NOT BE SOUTHEASTERLY ACROSS NORTH TEXAS ON TUESDAY...BUT
THAT`S NOT THE POINT. THE DRYLINE IS NOT REALLY A FRONT...BUT
RELIES ON STRONG WESTERLY TRANSPORT OF DRY AIR TO EFFECTIVELY MIX
A BOUNDARY EASTWARD OFF THE HIGH PLAINS AND TOWARDS NORTH TX.
SURFACE WINDS ACROSS NORTH TEXAS WILL NOT BE SOUTHEASTERLY BECAUSE
WINDS ALOFT WILL BE SOUTHWESTERLY...THE CORIOLIS FORCE WAS NOT
ACCOUNTED FOR...AND BECAUSE FRICTION WILL INFLUENCE THE WIND
DIRECTION. HOWEVER THE PRESSURE GRADIENT IS A DOMINATING FORCE
ACTING ON THE WIND FIELD...AND TO HAVE THIS FORCE MORE OR LESS
COUNTERACTING A TRUE WESTERLY WIND DIRECTION MAKES A DRYLINE
INTRUSION INTO THE CWA SEEM LESS LIKELY AT THIS TIME. AS A
RESULT...WILL NOT BE ISSUING A FIRE WEATHER WATCH WITH THIS
FORECAST PACKAGE...DESPITE OTHER CONDITIONS THAT ARE FAVORABLE FOR
ELEVATED FIRE DANGER TUESDAY AFTERNOON.

TEMPERATURES ON TUESDAY ARE EXPECTED TO CLIMB INTO THE UPPER 80S
TO NEAR 90 DEGREES NEAR THE SURFACE LOW AS MODELS SHOW A STRONG
THERMAL RIDGE ALOFT ORIENTED JUST SOUTH/SOUTHEAST OF THIS LOW.
SURFACE WINDS ARE EXPECTED TO BE OUT OF THE SOUTH-SOUTHWEST FOR
MUCH OF THE DAY ON TUESDAY WHICH REPRESENTS AT LEAST A LITTLE BIT
OF DOWNSLOPE FLOW WHICH WILL ONLY AID IN DEEP BOUNDARY LAYER
MIXING AND HEATING TUESDAY AFTERNOON. WITH TEMPERATURES WELL ABOVE
NORMAL AND LITTLE POSITIVE MOISTURE ADVECTION TO SPEAK OF WITH
H850 WINDS ORIENTED OUT OF THE WEST-SOUTHWEST...AFTERNOON RELATIVE
HUMIDITY VALUES WILL FALL BELOW 30 PERCENT FOR MOST AREAS WEST OF
INTERSTATE 35. THIS WILL SUPPORT AN ELEVATED FIRE WEATHER DANGER
WITH SOUTH-SOUTHWESTERLY WINDS OF 10 TO 15 MPH.

AS MENTIONED ABOVE...CRITICAL FIRE WEATHER DANGER WILL PROBABLY
NOT BE REALIZED UNLESS A DRYLINE MOVES INTO THE CWA TUESDAY
AFTERNOON. THE DRYLINE WOULD BRING STRONGER WINDS INTO THE
AREA...AND WOULD CAUSE RELATIVE HUMIDITY VALUES TO FALL INTO THE
SINGLE DIGITS TO ITS WEST. WILL CONTINUE TO MONITOR THE FORECAST
POSITION OF THE SURFACE LOW HEADED INTO TUESDAY...BUT DO NOT
EXPECT A STRONG DRYLINE INTRUSION INTO THE CWA OR THE ASSOCIATED
CRITICAL FIRE WEATHER DANGER AT THIS TIME.

TUESDAY NIGHT...THE SURFACE LOW IS EXPECTED TO MOVE SOUTHEAST
ACROSS THE CWA FROM TUESDAY EVENING THROUGH THE OVERNIGHT HOURS AS
A STRONG COLD FRONT RUSHES SOUTH ACROSS THE REGION. THIS IS IN
RESPONSE TO THE STRONG SHORTWAVE TROUGH PUSHING EAST OVER THE
CENTRAL PLAINS DURING THIS TIME. MODELS CONTINUE SO SHOW A VERY
STRONG FRONT WITH AN AGGRESSIVE NORTHERLY LOW-LEVEL JET OF 50 TO
55 KTS TUESDAY NIGHT. STRONG COLD AIR ADVECTION ALOFT WILL LIKELY
DESTABILIZE THE LOWER ATMOSPHERE DESPITE THE LACK OF ANY SOLAR
INSOLATION TO AID IN LOW-LEVEL HEATING. FORECAST SOUNDINGS ARE ALL
CONSISTENT WITH THIS THINKING...THEREFORE LOW-LEVEL MOMENTUM
TRANSFER SHOULD BE EFFICIENT...MEANING WE WILL BE VERY WINDY
BEHIND THE FRONT TUESDAY NIGHT INTO WEDNESDAY MORNING.

AT THIS TIME EXPECT THAT WINDS WILL BE SUSTAINED AT AROUND 30 MPH
GUSTING TO 40 MPH OR SLIGHTLY STRONGER AT TIMES. WINDS WILL REMAIN
BREEZY AFTER SUNRISE...BUT SHOULD DIMINISH IN STRENGTH SLIGHTLY
WITH THE STRONGER PRESSURE RISES HOLDING CLOSER TO THE LEADING
EDGE OF THE FRONT EXITING THE CWA. WEDNESDAY MORNING WILL LIKELY
SEE WINDS SUSTAINED AT 25 MPH OR SO...TAPERING OFF BELOW 20 MPH
AFTER NOON. THE CHANCES THAT WE WILL NEED A WIND ADVISORY FOR MOST
OF THE CWA ARE VERY HIGH AT THIS TIME. HOWEVER ADVISORIES ARE NOT
USUALLY ISSUED 48 HOURS OUT...SO WILL HOLD OFF ON THAT ISSUANCE
FOR NOW.

TEMPERATURES WILL BE MUCH COOLER BEHIND THE FRONT...WITH TUESDAY
NIGHT LOWS FALLING INTO THE MID 30S TO MID 40S FROM NORTHWEST TO
SOUTHEAST ACROSS THE CWA. HIGHS ON WEDNESDAY ARE EXPECTED TO BE
HELD IN THE MID 50S...DESPITE MOSTLY SUNNY SKIES DUE TO THE
PERSISTENT COLD AIR ADVECTION. NO PRECIPITATION IS EXPECTED ALONG
THE FRONT...PRIMARILY DUE TO DRY LOW TO MID-LEVEL AIR IN PLACE
OVER THE REGION.

REMAINDER OF THE FORECAST...TEMPERATURES WILL GENERALLY WARM UP
AFTER WEDNESDAY HEADED INTO NEXT WEEKEND. MODELS CONTINUE TO
INDICATE THAT A SHORTWAVE TROUGH WILL MOVE OVER THE CWA FRIDAY
AFTERNOON OR EVENING...SENDING A WEAK FRONTAL BOUNDARY ACROSS THE
AREA IN ITS WAKE. KEPT THE FORECAST DRY AT THIS TIME AS THE
TUESDAY NIGHT FRONT IS EXPECTED TO BE STRONG ENOUGH TO MOVE SOUTH
OVER THE ENTIRE WESTERN GULF OF MEXICO. THIS WILL INTERRUPT OUR
BEST SOURCE OF WATER VAPOR/MOISTURE RETURN TO THE REGION...
ESPECIALLY WITH MOST VEGETATION HOLDING IN ITS DORMANT PHASE AT
THIS TIME. IF MOISTURE RETURN IS BETTER THAN EXPECTED...MAY HAVE
TO INCLUDE SOME PRECIPITATION CHANCES ALONG THE FRONT FRIDAY
AFTERNOON OR EVENING...BUT NO SIGNIFICANT PRECIPITATION IS
EXPECTED AT THIS TIME.

MODELS CONTINUE TO SHOW ANOTHER STRONG UPPER LEVEL TROUGH MOVING
TOWARDS THE SOUTH PLAINS FROM THE NORTHWESTERN CONUS FOR THE
UPCOMING WEEKEND. THE 10/00Z ECMWF CONTINUED TO KEEP THE TRACK OF
THE UPPER TROUGH OFF TO THE NORTH OF THE CWA WHILE THE 10/00Z GFS
BRINGS THE TROUGH OVER TX JUST TO THE SOUTHWEST OF THE CWA. BOTH
MODELS EVENTUALLY SEND A COLD FRONT SOUTH ACROSS THE AREA IN THE
WAKE OF THIS STRONG UPPER TROUGH...BUT PRECIPITATION CHANCES AND
AMOUNTS ARE VASTLY DIFFERENT. IN GENERAL...A SOUTHERN TRACK TO
THIS UPPER TROUGH WILL GIVE NORTH AND CENTRAL TX MUCH BETTER
PRECIPITATION PROSPECTS THAN A NORTHERN TRACK.

JUST LOOKING AT THE OUTPUT FROM THESE MODELS MAKES IT SEEM LIKE A
COIN FLIP AS TO WHICH SOLUTION WILL VERIFY THIS WEEKEND.
UNFORTUNATELY THE CHANCES FOR THE 00Z GFS SOLUTION TO VERIFY
APPEAR TO BE MUCH LOWER THAN 50 PERCENT AS THE 00Z GFS DID NOT
HAVE MUCH SUPPORT FROM ITS ENSEMBLE MEMBERS. MOST OF THE GFS
ENSEMBLE MEMBERS FAVOR THE ECMWF SOLUTION WHICH OFFERS ONLY SLIGHT
PRECIPITATION AMOUNTS ALONG THE FRONT THIS WEEKEND. SIDED WITH THE
DRIER AND MORE NORTHERLY TRACK TO THE UPPER LOW AS A RESULT.

CAVANAUGH


&&



.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  78  52  82  41  56 /   5   5   5   0   0
WACO, TX              74  49  79  40  58 /  10  10   5   0   0
PARIS, TX             75  50  81  40  54 /   0   5   0   0   0
DENTON, TX            78  50  83  37  56 /   5   5   5   0   0
MCKINNEY, TX          76  50  80  38  56 /   5   5   5   0   0
DALLAS, TX            77  53  82  42  56 /   5   5   5   0   0
TERRELL, TX           75  51  78  41  56 /   5   5   5   0   0
CORSICANA, TX         74  52  79  43  57 /  10  10   5   0   0
TEMPLE, TX            71  49  77  40  58 /  20  20   5   0   0
MINERAL WELLS, TX     79  48  87  35  56 /   5   5   0   0   0

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

 /